Changes

Summary

1. Fix test for Hessians on faces with MatrixFree (commit: 96a5eb8) (details)
2. Extend references of HangingNodes (commit: d556186) (details)

Commit 96a5eb85194c8f7f978dbe26a4bb665fd909c14d by kronbichler Fix test for Hessians on faces with MatrixFree (commit: 96a5eb8)
	tests/matrix_free/matrix_vector_hessians_faces.output (diff)
	tests/matrix_free/matrix_vector_hessians_faces.cc (diff)
Commit d556186c7529796a12f4233272ecf9ad914ebe7f by peterrmuench Extend references of HangingNodes (commit: d556186)
	include/deal.II/matrix_free/hanging_nodes_internal.h (diff)
	doc/doxygen/references.bib (diff)